Timing light for kz750

I notice that one of the springs is maybe a little bent/stretched sort of thing. Maybe this is an issue. Where did you get your springs from?

Thanks

bobski911 wrote: I notice that one of the springs is maybe a little bent/stretched sort of thing. Maybe this is an issue. Where did you get your springs from?

Thanks

I bought the closest equivalents from Orchard Supply and made them. Royal PITA but nobody sells them.

Point is: if the weights have slop in them at rest, they advance some at idle which they should not do. To get the proper 30 degree advance from idle to 4000 RPM, the weights have to be tucked in fully at idle.

bobski911 wrote: Whoa whoa there turboguzzi,

I like the sounds of this, can you lead me to more info on the tools/parts, or procedure.

Thanks

bit too short in time to wirte full procedure.

basicall you attach a big timing or degree wheel to the alternator side and then zero the reading with the tdc tool, search "cam degreeing" and the first part of the procedure should be eay to understand

then use your gun at the wheel instead of the tiny rotor

Whether the springs are stretched out or not, the advancer should never go past the double lines. The springs just control the rate of movement, not the total limit of movement.

The limit to the movement, at idle, is made by little rubber pieces that can fall off. They look like tiny bits of dirt after they fall off and are easy to miss. When they fall off, you have to advance the ignition to get the F mark to line up. Then, at higher RPMs, the double lines will not line up, and the motor will be too far advanced.

The full-advance stops are the tabs on the advancer frame. Thos are hardened steel and should not bend.

Set your timing so the double lines line up at higher RPMs, then let the F mark be slightly retarded at idle. This is safer for the motor until you get the stops replaced.

loudhvx wrote:
The limit to the movement, at idle, is made by little rubber pieces that can fall off. They look like tiny bits of dirt after they fall off and are easy to miss.

That assumes the springs are holding the weights fully in. Problem is, the pins and springs wear until they have slop and have no resting tension. That means the weights are partially advancing at idle since they are not held in to where they should be. That eats up part of the total advance available. On mine it was 10 degrees advanced at idle.

If I set it to the correct point at idle, I was 10 degrees too retarded at full advance. Set it correct at full advance and I was 10 degrees too advanced at idle which made it hard to start and backfired sometimes idling.

bountyhunter wrote:

loudhvx wrote:
The limit to the movement, at idle, is made by little rubber pieces that can fall off. They look like tiny bits of dirt after they fall off and are easy to miss.

That assumes the springs are holding the weights fully in. Problem is, the pins and springs wear until they have slop and have no resting tension. That means the weights are partially advancing at idle since they are not held in to where they should be. That eats up part of the total advance available. On mine it was 10 degrees advanced at idle.

If I set it to the correct point at idle, I was 10 degrees too retarded at full advance. Set it correct at full advance and I was 10 degrees too advanced at idle which made it hard to start and backfired sometimes idling.

Yes, but he said that the double line moves past the mark. That means he has more movement than he should, so one of limits is off, and the most likely stop to be changed is the rubber one. If it was due to weak springs, he would have less movement than he should.

bobski911 wrote: ... The F didn't line up perfectly so I made a little adjustment. Everything seems to run fine, but in the manual I think it says "at 3800rpm, the mark should line up between the two lines". My bike goes past the two lines. ...

Hi guys, I too, a look at the mechanical advance unit and everything seemed tight with good tension in the springs. Didn't notice any sloppiness. It was also nicely lubed.

Just to clarify, I meant the mark on the engine case goes past the two lines on the advance mechanism at 3500rmp.

I will take a look if it has those rubber bumpers. I don't recall seeing them. What can be done if they are worn or gone?

Thanks

loudhvx wrote:
The limit to the movement, at idle, is made by little rubber pieces that can fall off. They look like tiny bits of dirt after they fall off and are easy to miss.

So I just checked the advance mechanism and it still has the black rubber pieces on both weights.

loudhvx wrote:

Would be certain of aligning the F mark, and not the T mark or any other mark, at the lowest possible idle rpm, so as to assure the weights are fully closed.

With the rubber stops in place, and no apparent damage or alteration to the full advance stops or the arms (weights), would set timing by aligning the double marks at higher rpm. Then observe the F mark at the lowest possible idle rpm.

Absent damage to the advancer, or alteration, am uncertain as to what condition might cause the reported failure to align between the F mark and double marks. Perhaps an incorrect advancer is fitted?

Good Fortune!

Patton wrote:

loudhvx wrote:

Would be certain of aligning the F mark, and not the T mark or any other mark, at the lowest possible idle rpm, so as to assure the weights are fully closed.

With the rubber stops in place, and no apparent damage or alteration to the full advance stops or the arms (weights), would set timing by aligning the double marks at higher rpm. Then observe the F mark at the lowest possible idle rpm.


Good Fortune!

So its more important that I have the mark on my engine case be in between the two lines, rather than it be lined with the F? Is it okay if its just past the two lines? If there was another line after the two lines, my mark would be in between them.

Going more advanced than the double lines is risky since that can promote knocking. Maybe someone with racing experience will know if it's safe or not on your motor. I suspect not.

Being slightly after the F mark at idle might make the idle a little less smooth and consistent, but it should be safer for the motor than going too far advanced at high RPM with high load.

But, really, the ideal thing is to fix whatever is causing the advance to have too much travel.

loudhvx wrote:
But, really, the ideal thing is to fix whatever is causing the advance to have too much travel.

Should be fairly easy to fix. On mine there are metal "pads" that limit the travel of the weights. Get some silver solder and solder up some "meat" onto the pads there then file them down to adjust travel distance.

The figure above shows them as "advanced stop".

Would double check again because it is very odd the get too much advance, always see the other way.